In the relevant technical language, the term “belt” is on the one hand understood to mean the circulating belt in a belt conveyor and, on the other, a complete belt conveyor device. For the purpose of this description, the term “belt” is used for conveyors while the term “web” is used for the actual belt circulating in the conveyor.
Functional belts are belts which fulfill other functions as well as the conveyor function. At the same time, functional belts are main belts, i.e. wide belts which correspond to the width of the production process. One form of functional belts is so-called control belts which are usually of very short design in the range between 100 mm and 400 mm in length.
Control belts are very often positioned at the beginning of a feed system and are used for the correct functional transfer of freshly produced rows of product. The feed system receives the freshly produced rows of product and transports them, appropriately indexed, to the packaging machines. In biscuit production, the width of the main belt is oriented toward the width of the oven. In the case of chocolate or chocolate bar production systems, the width of the main belts is oriented toward the width of the molds. Typical main belt widths therefore vary from 600 mm to sometimes more than 2000 mm.
Control belts receive the freshly produced naked products from the production belt in a synchronized manner, usually arranged as rows, and then deliver these rows of product to the packaging machine feed system. In doing so, it may be that the rows of product are formed and delivered on the production belt at varying speed. Likewise the rows of product can be formed and delivered as a closely grouped formation. This results in the task and function of a control belt. A control belt receives the rows of product or product formations from the production belt in a synchronized manner. Here, the delivery may occur at constant speed or at varying speed. The delivery of the rows of products to the packaging machine feed system lies on the one hand in the distortion-free transfer to a higher constant transport speed and, on the other, in the timely indexing or separation of the rows of product to the feed system. Indexing and separation is usually necessary with rows of product which are to be transferred from the production belt in formations.
Knowing the function and the location of such control belts results in the problem of contamination. Contamination is increased, as the freshly produced products are dynamically loaded onto these control belts. That is to say, the rows of product are accelerated and retarded. In doing so, slip and therefore abrasion can occur. Crumbs (product crumbs) or faulty (deformed) products in the transfer region often have to be taken into account. All this leads to increased contamination and, as a consequence thereof, to increased cleaning effort. This is because contamination is the cause of all kinds of efficiency losses. On the one hand, the loss can be the cleaning time, in which no production can take place, and, on the other, malfunctions and faults are the cause of increased rejects.